CREATE TABLE `parent` (
  `parent_id` int( 11 ) NOT NULL auto_increment,
  `name` varchar( 32 ) NOT NULL default '',
  PRIMARY KEY  (`parent_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT= 3  ;

INSERT INTO `parent` VALUES ( 2 , 'parent1');

CREATE TABLE `child1` (
  `child_id` int( 11 ) NOT NULL auto_increment,
  `parent_id` int( 11 ) NOT NULL default '0',
  `name` varchar( 32 ) NOT NULL default '',
  PRIMARY KEY  (`child_id`),
  KEY `parent_id` (`parent_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT= 3  ;


INSERT INTO `child1` VALUES ( 1 ,  2 , 'child1_1');
INSERT INTO `child1` VALUES ( 2 ,  2 , 'child1_2');

ALTER TABLE `child1` ADD CONSTRAINT FOREIGN KEY (`parent_id`) REFERENCES `parent` (`parent_id`) ON DELETE CASCADE;

CREATE TABLE `child2` (
  `child_id` int( 11 ) NOT NULL auto_increment,
  `parent_id` int( 11 ) NOT NULL default '0',
  `name` varchar( 32 ) NOT NULL default '',
  PRIMARY KEY  (`child_id`),
  KEY `parent_id` (`parent_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT= 3  ;

INSERT INTO `child2` VALUES ( 1 ,  2 , 'child2_1');
INSERT INTO `child2` VALUES ( 2 ,  2 , 'child2_2');

ALTER TABLE `child2` ADD CONSTRAINT FOREIGN KEY (`parent_id`) REFERENCES `parent` (`parent_id`);